What constitutes a dive? Is a day of diving considered a dive or is there another benchmark?
Are types of diving (lake, quarry, etc) regarded higher or lower for experience than others?
Thanks!!
This is a difficult question. A more relevant metric would be the time spent under water.
Some agencies, however, like to know the number of dives.
Usually this is obvious. You assemble the breathing apparatus, put it on, and dive. When you take it off the dive ends. If you then put on a new tank and dive again eg. after an our or two then a second dive begins. You may do a couple of dives per day. If you surface, float a few minutes, and dive back down, then the original dive continues.
It gets a little bit complicated with short dives: I once logged a 50 second dive and I DO think that it was a proper dive. This was an icedive with two hours of ice cutting, gearing up, dive planning, ... everything... and then a descent to 9m where my regulator started to free flow. I was unexperienced so I got a bit stressed and many unpleasant things happened and I learned a lot. Because I learned a lot and also because of the preparations, I counted this as a dive. Well... the ten pages of analysis in my logbook kind of hint that counting it as a dive was the correct thing to do.
If I explore a new shallow zero viz site, then I may do maybe five dives that are a couple minutes long and maybe ten feet deep. I count these dives as one dive. It is a (SCUBA) dive because it cannot be done on breath hold. The challenge, preparations, things learned, pages in logbook, ... it all hints that this should be counted as a dive. But not five though. The idea is not to dip yourself in a lake like a teabag in a mug.
If I dive under solid ice, then the dive may be only one to three feet deep, but it IS a dive. The ceiling acually makes it a pretty serious dive too. I have also done some pretty amazing dives that were almost two hours long but the maximum depth was ten feet. As I stayd submerged it was not swimming. It is obvious that it was a dive.
Only in extremely rare cases do I count as a dive anything that is shorter than 20 minutes. The only exceptions are some specific ice/cave dives.
So... what does constitute a dive? Answer: it's up to you, but it certainly is a dive if you have a lot to tell.